Hi - might be worthwhile to try a trial version of a photo recovery programme and see if you can recover your photos. There are many out there and here is a link to one of them..... http://www.datarescue.com/photorescue/
Perhaps someone else with an SD card can let you use their's to establish if the fault lies with your camera. Try copying the total contents of your card to a directory on your PC's harddisk and then try to open the photos using a standard graphics programme. I would not suggest that you format your card via your PC but rather via the menu as indicated on-board your camera.
Cheers - Herman